initramfs, abbreviated from "initial ram file system", is the successor of initrd. It is a cpio archive of the initial file system that gets loaded into memory during the Linux startup process. The Linux kernel mounts it as root file system and starts the init process from it. This will complete certain tasks before the real root file system is loaded; thus, initramfs needs to contain all of the device drivers and tools needed to mount the real root filesystem.

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</blockquote>

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== Do I need an initramfs? ==

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{{#ask: [[CPU Family::{{PAGENAME}}]]

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The reason to build a kernel with an initramfs is mostly for interoperability (e.g. live-cd's) and special features like an included busybox, ssh, etc. But mostly, and that's why we are doing this here now, to have a proper kernel up and running quick'n dirty in a reasonable time without fighting hours and days until a more or less exotic hardware is perfectly run by the kernel. After having a proper basic kernel running with the help of an initramfs, I really recommend you to go a step further and build a true kernel with all features includes without an initramfs. However, relying only on a kernel to boot a system can be quite time consuming, so we have provided several initramfs options for Funtoo. If you have decided to use an initramfs, not just a kernel, check out the options below and choose the one that you like the most.

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| ?subarch

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| mainlabel=-

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== better-initramfs ==

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| format=ul

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Piotr's better-initramfs is a popular approach among Funtoo'ers to building an initramfs. It is quick, nice, and shiny. The biggest plus is that, once built, it is kernel version independent.

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=== Installation ===

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To install better-initramfs on your system, change to the <code>/opt</code> directory (or any other directory that you deem suitable) and clone the better-initramfs repository from bitbucket.

Now that you have better-initramfs on your system, we can make the <code>initramfs.cpio.gz</code> image and move it to <code>/boot</code>.

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{{fancynote| do not run <code>make prepare</code> or <code>make image</code> until you have configured your kernel. If you have not installed / configured a kernel yet, check out: [[Building_a_Kernel_from_Source| Building a Kernel From Source]] and [[Funtoo_Linux_Kernels| Funtoo Linux Kernels]].}}

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<console>

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###i## cd better-initramfs

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###i## bootstrap/bootstrap-all

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###i## make prepare

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###i## make image

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###i## cp output/initramfs.cpio.gz /boot

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</console>

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=== Configuring <code>/etc/boot.conf</code> ===

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Now that the <code>initramfs.cpio.gz</code> file is in <code>/boot</code>, we can configure what we want the initramfs to do for us when the system boots. Below is a table of options that better-initramfs supports (from [https://bitbucket.org/piotrkarbowski/better-initramfs better-initramfs Bitbucket page]):

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==== Options ====

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{| {{table}}

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!Option

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!Description

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|-

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|rescueshell

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|Drop to the rescueshell before mounting rootfs to <code>/newroot</code>

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|-

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|sshd

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|Run the sshd server when the initramfs loads. This allows you to ssh into your initramfs to fix any errors that may have occurred while booting.

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|-

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|sshd_wait=x

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|Wait x number of seconds after starting sshd to continue booting the system.

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|-

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|sshd_port=x

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|Change the port that sshd "listens" on. The default port for sshd is port 22.

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|-

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|binit_net_if=interface

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|Choose which interface the network should be configured on. For example: wlan0, eth0, etc.

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|-

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|binit_net_addr=<ipaddr/cidr>

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|Configure <code>ipaddr</code> with <code>cidr</code> netmask. For example: <code>11.11.11.2/24</code>. If you do not add a netmask, the netmask is assumed to be 32. Furthermore, you will have to configure <code>binit_net_gw</code>.

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|-

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|binit_net_gw=ipaddr

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|The address of your gateway. Only needed if you want to connect to WAN.

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|-

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|rw

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|Mount the rootfs as read-write. By default, the rootfs is mounted as read only.

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|-

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|mdev

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|Use mdev instead of devtmpfs. This option can prove handy on older kernels.

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|-

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|softraid

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|Detect and run RAID arrays.

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|-

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|init=

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|Change the init system. For example, if you are using systemd, change this to <code>/usr/lib/systemd/systemd</code>. The default for this option (<code>/sbin/init</code>) will work fine with OpenRC.

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|-

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|tuxonice

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|Try resuming with TuxOnIce.

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|-

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|uswsusp

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|Try resuming the system with userspace software suspend. This depends on the <code>resume</code> option.

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|-

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|swsusp

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|Try resuming the system with in-kernel suspend. This depends on the <code>resume</code> option.